1. Field of the Invention
This invention relates to a dolly for connecting a second trailer to a lead trailer.
2. Description of the Prior Art
Heretofore, a tandem trailer dolly has typically comprised an axle, wheels rotatable thereon, a fifth wheel secured to the axle, and one or two points for connecting the dolly to the rear of the lead trailer.
If only one point for connecting the dolly to the rear of the lead trailer is used, the structural arrangement of the known prior art devices render it practically impossible to control backing up of a tractor with tandem trailers attached thereto. Such exemplary prior art devices are shown in U.S. Pat. No. 3,717,363 to Berends, U.S. Pat. No. 3,827,723 to Neff et al., and U.S. Pat. No. 3,912,302 to Patterson.
However, such controlled backing up of the entire rig is facilitated by those prior art dollies which have two points spaced apart for connecting the dolly to the rear of the lead trailer. Such exemplary prior art devices are shown in U.S. Pat. No. De. 233,322 to Schantz, U.S. Pat. No. 3,421,777 to Barker et al., U.S. Pat. No. 3,612,575 to Stewart, U.S. Pat. No. 4,162,082 to Curry, U.S. Pat. No. 4,400,004 to Arguin, and U.S. Pat. No. 4,451,058 to Curry. Nevertheless, none of the prior art devices disclosed in these patents allows the second trailer to be hooked to the rear of the lead trailer on uneven ground. Also, the rigidity of the two separate points connecting the dolly at the rear of the lead trailer tend to cause the rear wheels of the lead trailer to drag sideways or "scoot" during moves through curves and turns.